GregBBRD

We did not. Removed the experimental pan and scraper. Installed the pieces that had been working fine.

I actually do not increase the pan capacity. I lower the oil level, on the dipstick. I'm trying to get the oil away from the crank, a bit more. This also gives me the opprotunity to custom locate and fit the pick-up, so that the pick-up has an optimised venturi design.

I do not completely agree with your thought that the fins in the bottom of the pan were designed a "scraper". I think that these are simply "return channels" to guide the oil back to the sump, as the oil flies off of the crankshaft. My windage trays are made from the same material that Carl is using...the are screen that only lets the oil flow through them one way. They, therefore, so not interfere with the stock pan's function.



No, the oil blows right through the screen, in my design and then hits these pieces on the pan, which guide the oil back to the sump area. The idea of the "one way" screen is to simply allow the oil to blow through the screen and not allow the oil to be picked back up by the crankshaft.

That's why I built what I did. I don't have the time or ability to test a design like Carl's and Kevin's, which may work great, but certainly might impeed the returning oil. Since I've found that people tend to "run and hide" when one of their products fail or cause problems, I tend to look at things and design pieces that I know will work. I then test them, for years, before they get sold to anyone else. I'm not trying to make a living off of my products. They are mostly made for my own use. If someone else likes them and wants to use them, I will try and help, if possible.

Note that the amount of available oil, in the sump, at high rpms is certainly only measured in "seconds of available use". Slowing that oil down returning to the sump, could be a disaster. I can't say that this will happen with their design, but I know my stuff does not do this. It simply allows the oil to pass right through and then keeps it away from the crankshaft.

It is important to remember that oil is flying off of the crankshaft 360 degrees of rotation....there is actually more oil flying off the crankshaft above any windage tray/scraper system, than there is below that system. That oil needs to be able to get back to the sump without any restriction, in my mind.

Exactly....that is why I built what I did.

mark kibort

could the windage tray impede the flow back to the pan? if so, that would or cause a oil starvation problem, and the question is , whether it is possible or probable that other bearings besides the 2-6 could fail first, or does it have to be 2-6?

I dont know squat about this stuff either, except for the high level. certainly, i believe that if you install this stuff, you should have a reason and proof that it does work and will achieve the goals. right now, im not really clear what those goals really are. In my mind, find the guys that are using our engines at the limit without issues and do what they do.

mk

Kevin Johnson

In the original expression of the 928 sump they were two mm closer to the rotating assembly. Porsche could simply not afford to alter the casting. Ford had already utilized this scraper technology in the 1960s FE, of which Porsche would have certainly been aware. When Porsche became a bit more flush with funds they redesigned the pan casting and raised the scrapers [edit: ...in the derivative four cylinder]. The 928 had long since been relegated to GT status.

Prior to using the directional screening I had talked with Ed Peters, a failure analysis engineer at Dodge. He was in charge of solving the aeration and foaming problem with the factory Shelby Turbo cars back in the 1980s. Dodge and Mobil performed joint research on the problem. This problem was solved by using directional screening. Ed compared the effect of directional screening to trying to splash a drink of water through a screen door. The action is highly damped -- the screening absorbing much of the energy. That is critical in order for the drops to not aerate the sump oil beneath. Naturally the screening does allow draining to the floor of the pan. We disagree on the use of or identification of technology. This is why I think it is important to look at other marques and see what was typical of the time for high performance. The OEMs certainly buy and dissect each others offerings.

Directional screening is iterated small louvers. Oil does blow right through large louvers. The desired effect with directional screening is to reduce the velocity of the oil droplets.

Incidentally, the use of dedicated scrapers within directional screening trays is well proven technology.




This is why it is important to make the effort to look at and analyze extant technology over a broad time period and over a large cross section of engine families and marques.

I hope this is not an oblique critique on me. I have designed and made more windage control products for more different engines from more marques than any other company in the world. That was already true back in 2005 when I was ASKED to develop a product for the Porsche 928 by this community.


I suggest doing a bit more background research. Start with the Nissan RB26DETT with three levels of windage trays. Also, the construction of windage trays has diametrically opposed aims. Your windage screen, like all such designs, does not prevent the ingress of oil under steady acceleration which is the failure mode of the 928. It is a compromise, like all designs.

I think that you might just find your statement is incorrect. Of the top of my head the scraper system for the BMC operates from quadrants one through three. That is more than 180 degrees. If you need more examples, please let me know.

I am not trying to be a jerk. I take my work as seriously as you do, that's all.

GregBBRD

Obviously, if you've been on Rennlist for any period of time, you probably know that Kevin and I are not and never have been, on the same page. That's OK. He's entitled to his ideas and I'm entitled to mine. Note that he builds windage tray systems and that I build uber reliable track and street proven complete 928 engines with products that are and have been tested for long periods of time....before they are sold.

For those of you new to this debate...here's the essential difference:

Kevin thinks that all the problems with oiling on the 928 model are a result of air being trapped in the oil and that this can all be solved by a windage/scraper system. He has an infinate amount of examples (that mean absolutely nothing to me....I just know 928 engines) that support his theories. When he suggests that I go look at a Nissan RB26DETT, he might as well have written this in French....I don't even know what that is...and the odds of me ever even seeing one are....zero.

I believe that the problem with 928 oiling is a multi-issue problem and it takes more than one thing to solve this problem. Proof of this? I've been doing 928 engines for a long time. I've built dry sumped and wet sumped engines. We had to make oiling changes to the dry sumped engines to get them to survive. The Porsche factory built the 944 GTR engine, which has very similar oiling issues. It was dry sumped. They "spit out" connecting rods like they were made of glass, until they addressed the oiling issues....beyond the dry sump system.

Kevin's system might be the best thing, since sliced bread. I actually don't know.

I can tell you this: His system is very nice looking and seems to be an excellent value....if it works. I would hate to have to build his system for what he charges to supply it. Fabricating all those little pieces and securely sticking them together takes some serious time!

I would be more than happy to test one of his systems, on an engine. It just needs to come with a warranty. If it screws up the engine, I need someone, besides me, to pay to fix it. Pretty simple. I'm tired of trying other people's theories on my dime, especially when I've already solved the problem.

Carl Fausett

Some of the posts look like the very vailidity of a crank scraper in a 928 is being challenged. Just a reminder this is not new technology for either a V8 in general or a 928 V8 in particular. We have years on these things and a lot of track time.

I've been running and testing the IJ crank scrapers in my race car since 2003. A number of us contributed ideas to Kevin in 2006 and 2007 (not just me) and the improvements Kevin made to the 928 system have been measureable.

I can tell you how long it used to take me to fill my catch tank in the supercharged race car before and since those changes.

For example, this year, I ran a 20-minute and a 30-minute race at Road America back-to-back without servicing the car other than to add fuel. It didn't need oil, coolant, or the catch tank emptied. Thats almost an hour of racing under boost.

Road America used to be my catch-can nemesis. While I could run most 2-mile-per-lap tracks just fine, the 4-miles per lap of Road America, the many lengthy pulls at WOT, and the high lateral G's in the carosel made RA our scarey track where oil pressure and catch can filling were concerned.

Add that I also have never had a engine bearing failure, in spite of years of torterous racing the 928.

These are all items that a complete, well designed, and fully tested crank scraper and windage tray system affects. I am very happy with the results obtained and thats why they are in our catalogs.

Kevin Johnson

Yes, what I do is examine the work of thousands of automotive engineers over decades and note what they have tried and continue to use successfully over myriad engine designs. I follow up on that with reading feedback often over decades on those technologies -- the Merlin engine, seventy years ago. From that I extract sound and accepted engineering principles which can be found cited as commonly acknowledged background knowledge for specialists in windage control. This is why the OEM 2003 Gen III Viper V10 crank scraper looks very similar to that found in my Porsche designs, for example. It is why GM cites it in their patents.

I have not made ONE directional screening design for ONE engine. I have made at least hundreds. I read about the technology. I read decades of feedback about this product which has been sold for at least 30 years. Because of that study I do not use large unsupported expanses of this material despite the encouragement of that technique by some very well known aftermarket manufacturers. When people call me I often take hours out of my day to painstakingly tell them how to safely construct such a design. I offer to sell them material basically at cost. My accountant read me the Riot Act a few weeks ago.

For those of you new to this debate, this attention to technology over time and across brands is why, when I looked at just _pictures_ of the interior of a M96 for the first time I was able to solve a decade long standing engineering problem in about two hours. Behind that were years of study and hard work.
~~~~~~~~
Aside:

Thanks, Carl, for your long standing support.

Carl Fausett

Regards how expensive our crank scraper and windage tray system is: it's still cheaper than a complete dry-sump system. And cheaper than a blown engine.

If you got the money, go dry sump. But one problem here is that there are no commercially available kits for dry sumping your 928. You can buy a sump kit, make your own brackets, etc - but nobody will part with detail drawings of tested and proven dry sump oil pans for the 928. Schematics of oil pan designs someone is "gonna" build dont count. I haven't seen a schematic of a proven 928 dry sump pan.

So the wet-sump improvements we offer fill a niche. Not as expensive as a dry sump system, and they are race and street proven over a number of years. Thats a good deal!

I like to keep in mind that if its too expensive to race a 928, it wont get raced. I like the lower cost of the wet-sump system. Add the crank scraper and an Accusump and go racing! Its a solid combination.

GregBBRD

I assume you are telling the truth....and my statement, that you quoted, is still true. I think we agree!

GregBBRD

I agree with this, too. I've got one engine that is dry sumped and all the rest are wet sumped.

GregBBRD

I'm glad that his system works so good for you and has solved all the problems with your oiling issues....just one minor, silly question.....if it works so fricking good, why are you changing it? Why are you changing the design and adding screens? Won't that require another complete round of testing before actual sales can take place????

Look....here's the problem for the people on Rennlist. For every success of Kevin's stuff, there is an opposite horror story about a failure. I got two of them PM'd to me, today. I don't think you will ever find that, with my pieces, or engines.

Lord only knows what happened, so I'm not judging the system from rumors or claims. I'm not judging it at all. I'm simply saying that what I've done has solved the problem and I don't need to "experiment" with unknown pieces.

Kevin Johnson

Greg, you have already confirmed that screens do work. There is nothing mystical about screens or how to apply them correctly. The only thing that I have seen in the discussion is that I have correctly identified the existing factory technology and stated that screens are a compromise with respect to that. So your testing confirms what is already accepted practice. Congratulations.

The original design for the scraper system included a tunnel to enclose the rotating assembly. If you break out of your isolation and look at the windage tray that GM developed for the Corvette LS a decade or so ago you will see what I mean. Because the architecture of the engines is similar they have similar windage issues and failure modes. The rear of the Batwing pan allows oil to collect on the secondary windage tray and flood the primary tray interior.

When I attempted to close the pan with the used gasket on the engine I was lent there were too many contact points. So I ground away and ground away until only the remnants remained. My constraints were the factory components and OEM gaskets plus the fact that I needed to return the engine. Later that year I brought in an order of directional screening. When I was able to purchase a core instead of using a jig I could continue on the central tunnel development.

There were many other changes. If I could improve the design, I did so.

Greg, I wish you the best of luck with your windage screening the way it is. I suspect that I have already talked to more people about their experiences with directional screening windage trays than you will in the remainder of your lifetime. They have a tendency to break apart over time if they are not supported properly in large areas. Some people never have a problem. Others swear off the material completely.

If you would like to know how to fix your design it is pretty straight forward. But that would be an experiment, right?

ptuomov

Just thinking out loud here. Suppose that one optimizes the stock oil pan full level. It's a compromise between many factors. Then, suppose that one optimizes the oil pan full level when a spacer is fitted. I would have thought that some of the extra room would be used for extra oil. Not all of it, but some. In any case, I haven't experimented with this so I of course believe you.

Whether we call it a scraper or not is just semantics. I think the substantive question is whether the original factory pan design expects the oil to hit the fins with high velocity or low velocity in order to work. I guessed high velocity.

If high velocity is needed for these pan fin devices to work, then they are not working with the windage screen between them and the crank. Now, since you, Kevin Johnson, and Louie Ott all think it's better to put the windage screen between these pan fin devices and the crank, I am certainly not going to make a confident case that it's a bad idea to do so!

I have not understood what makes these screens "unidirectional." Perhaps they slow down the oil and let gravity works it magic. Is there some other way in which the screen is unidirectional, like an electrical diode? This question obviously exposes my ignorance.

I agree that one should try to keep the pickup submerged. Important part of that is keep the oil moving towards the deep end of the sump. That's why I am surprised that you are not filling the sump any fuller after you install the spacer. I am also surprised that everyone who has really worked hard on the problem has decided that covering the fins sticking out of the bottom of the pan is an improvement.

I agree that the pan and oil level being so close to the crank is a problem. I am a bit surprised that your design doesn't incorporate a pan spacer and a spacer for the pickup. Is this just a cost issue, or is there some other reason why you don't use a spacer?

So when a droplet hits oil surface hard, air gets mixed in. For this reason, it makes sense then that the deep part of the pan is covered with the screen. However, does it really make sense to cover the shallow part of the pan with the screen for that reason? If the purpose of the screen is to stop the oil from rebounding back to the crank, then I can see the logic of putting the screen on top of the shallow part.

There's only so much purely commercial R&D that the 928 aftermarket can support. Some of the testing and R&D (and the associated risk and cost) will always fall on the customer in a small market like this. It's just the way it has to be. Otherwise, no progress will be made.

Most designs that work can be made better. I think it makes sense for everyone to try to tweak and improve the product, even if already works adequately.

GregBBRD

Well, I agree that I'm isolated. I also agree that you probably have forgotten more about this subject than I'll ever know.

I also really dislike making windage tray screens....it takes a lot of time and I've got other things to do. I'd be really happy to get together with you and have you build a simple, windage control system. I guess I'm afraid of the intricate scraping system...I'm afraid of traping oil above the crankshaft or slowing its return to the sump. The volume of oil that gets delivered to the cylinder heads in these engines is huge and I'm afraid of making changes that could possibly interfere with this oil returning, also.

Kevin Johnson

I will be in contact with you, Greg. I do not know if I will have the time either but I am certainly amenable to helping.

There are reasons the design below lifted so much oil at high rpms. I believe this is the right pic; it has been several years. I will take it down it there is a problem.



The overall design when taken with the direction of rotation and prevailing high speed windage flow acts as a ramp pushing ejected oil back into the rotating assembly. The angle of attack of the trailing scraper is wrong. Use its supplement, I think, but it is still shrouded.

The forward collection area would act as a crude scraper until the windage flow was great enough to pressurize it locally and then allow the balance of the flow to glide over it.

Carl Fausett

Who said I'm changing it?

This post was just announcing that I am adapting the current crank scraper and windage tray system to fit our stroker crank. This crank is made by Moldex for us (I'm going to be asked, so I might as well mention it).

I wanted the guys to know that a crank scraper system for a stroker crank was going to become commercially available in the near future.

The longer stroke, and the large con rod journals of the rods we use created new clearancing issues.